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Interview (Mr. Zouhair Kefi)

“Energetica India: Congratulations on the launch of REFUsol 100K. Please help our readers understand the unique features of this string inverter.

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Zouhair Kefi: Thank you very much – we are happy and proud to launch this new platform for high power solar inverters starting with the REFUsol 100K.

When looking at the REFUsol 100 K, one feature that directly catches the eye is the two-piece design. The Connection Box and Power Unit are two separate items, but arranged behind each other to optimize installation space requirements. In addition, the Connection Box serves also as the mounting bracket. This special feature enables a time-shifted installation and thus cash flow optimization and extension of inverter lifetime for the customer: The cable connection for the plant can be completely prepared with only the Connection Box, the Power Unit can be hooked up at a later stage with easy plug and play connection to the power unit. This implies also that the power unit can be quickly detached from the ConnectionBox for trouble shooting and measurements without disconnecting the power cables on the DC and AC side, as well as a fast and easy exchange process.

Besides this obvious unique feature, the new REFUsol 100K also offers easy and fast connectivity for the customer. We decided to simplify the inverter display and provide a smartphone app for commissioning, configuration and monitoring. The app is usable via direct wireless connection and available for iOS and Android smartphones. The integrated, fail-safe ethernet daisy Chain (alternatively RS 485) allows cost efficient high- speed monitoring without special accessories. Each inverter is individually connected to REFUlog for professional monitoring, configuration and remote firmware updates.

We are proud that we can offer our customers a convincing full package for large-scale projects pairing these mentioned technological features of the REFUsol 100K with our 50 years’ experience, German quality and our worldwide presence.

“Energetica India: How has Refusol's Indian journey been so far? What are your future plans for the Indian market?

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Zouhair Kefi: As people know, we already have a long history in India since the start of REFUsol inverters more than 10 years ago. We are connected with India and its solar market in different ways.
On one hand, we have a R&D department in Pune, where our colleagues work hand in hand with the German R&D centre on new developments. On the other hand, we are present in Bangalore and Noida with sales offices of the worldwide Prettl Group (which REFU belongs to) and we provide local service for after sales through our repair centre in Pune.
Giving an outlook for the future: we are evaluating local assembling opportunities in India for the local market and hope to be able to share outcomes of this soon.

“Energetica India: Where do you see the cost trends going for solar inverters?”

Zouhair Kefi: From our point of view, the massive price decrease for solar inverters will not continue, but prices will stabilize in the next 2-3 years. We think that the technological limits are currently reached when it comes to power technology and if there is no massive price decrease in single components of inverters, we expect a stabilization of costs.

“Energetica India: How do you see the demand for string inverters going forward compared to central inverters?

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Zouhair Kefi: From what we see, the demand for string inverters is already increasing compared to central inverters and we expect this trend to continue. With the high power classes reaching 100kW per unit, string inverters are perfectly suited even for utility-size scale. There is nearly no difference anymore on the CAPEX, while string inverters offer better OPEX.
Different studies that we performed showed that plants with string inverters installed in a centralized design offer the best economic outcome for the customer with the least risk. Therefore we have developed the concept of REFUcube, which is the first maintenance- free containerized solution with integrated string inverters. It provides a centralized string inverter solution with fast deployment, higher yields thanks to more MPPT’s than central inverters as well as minimized costs and risk for the customer.

“Energetica India: How important has storage become for renewable energy? What products does Refu Elektronik offer in this space?”

Zouhair Kefi: Storage will become the most important puzzle piece for renewable energy in the next two decades, as it will be necessary for the integration of renewables into the power mix and for an efficient usage of renewables around the clock.
As mentioned earlier the REFUsol 100K is a development based on a new inverter platform. We are using this platform for both – solar and storage developments. Thus the upcoming launch will be a storage inverter based on the 100K platform and our product roadmap contains additional products for solar and storage applications in the next year. Customers should keep a close eye on us.

“Energetica India: How is the solar inverter market growing in terms of size and geography?”

Zouhair Kefi: The solar market worldwide is not only growing in terms of size, but we also see an increase in the number of countries using solar energy. This trend will certainly continue, as the potential for solar energy globally is not even close to being exhausted.
The different markets are very diverse in terms of geographical location, governmental regulations as well as maturity. The challenge for REFU as a manufacturer of solar inverters is to provide the right technology for the different markets and requirements –but with our long experience and large expertise in power conversion, we are very confident to be well equipped for these challenges.

“Energetica India: How is the solar inverter market growing in terms of size and geography?”

Zouhair Kefi: The solar market worldwide is not only growing in terms of size, but we also see an increase in the number of countries using solar energy. This trend will certainly continue, as the potential for solar energy globally is not even close to being exhausted.
The different markets are very diverse in terms of geographical location, governmental regulations as well as maturity. The challenge for REFU as a manufacturer of solar inverters is to provide the right technology for the different markets and requirements –but with our long experience and large expertise in power conversion, we are very confident to be well equipped for these challenges.